TPS61261: Power consumption when Disabled

Hi Jasper,

Thanks for the reply. Sorry I meant 0.05-0.06mA (50-60uA).

OK. this value is larger than the spec. in the datasheet.
1. did you see this in every devices or just one device.
2. could you share the schematic?
3. please measure the voltage at every pins of the TPS61261 and share.

Hi Jasper,

I tested two chips. They both have higher shutdown current than specified. I am currently using it soldered onto prototype adapter board:

www.proto-advantage.com/.../product_info.php

Also, the enable pin seems to be drawing 0.25mA current when its tied to Vcc.

I'll get more information about pin voltages and post more information tomorrow. In meanwhile, what are some common causes for higher than normal shutdown voltage?

Thanks

I meant higher shutdown current.

Hi Jasper,

I tested with CR2032 battery for 3V and nothing connected to Vout. I tried both tieing the Enable pin to GND and the Vdd (battery). The lowest current consumption is about 14uA when I tied the Enable pin to GND and 47uA when I tie the Enable pin to Vdd. 

Here are the voltages for each pin when enable tied to GND:

R1, EN - 0V

Vin, L - 2.96V

FB,Vout-1.56V

Here are the voltages for each pin when enable tied to VDD:

R1 - 2.46V

EN, Vin, L - 2.88V

FB, Vout - 3.36V

Thanks

The current at EN to VDD is normal, because the device is switching.
however, the input current at EN=GND is too large. could you try to discharge the VOUT to zero voltage at EN=GND condition?

Hi Jasper,

After the discharge Vout-zero at EN=GND and at EN=GND condition, after I restarted it a few times, the circuit drawing either around 8uF or 10.5uF.

Thanks

After discharge VOUT to zero, and EN=GND, what happen?

Hi Jasper,

I did more testing. After discharge VOUT to zero, and EN=GND, the circuit drawing around10.5uF.

If I restart the circuit immediately without discharging, it is drawing around 8uF.

Thanks

Michael

i'll do some experiment with EVM to check if i can find similar behavior.

I do some measurement, the shutdown current is smaller than 1uA. i'm not sure why you see large large leakage current. maybe it is caused by the measurement method. could you add a 1k resistor in series with the power supply, measure the voltage drop through the resistor at EN=L.
I would also suggest you apply an EVM for reference.